FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes a member of the type 3 G protein-coupled receptor family. Members of this superfamily are characterized by a signature 7-transmembrane domain motif. The encoded protein may modulate insulin secretion and increased protein expression is associated with type 2 diabetes. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2015] PHENOTYPE: Mice homozygous for a reporter allele exhibit partial neonatal and postnatal lethality, altered spontaneous activity pattern, and decreased response to a new environment. [provided by MGI curators]